Envisat keeping an eye on the Eyjafjallajoekull volcano
The development of the ash plume from Iceland's Eyjafjallajoekull volcano between 17-20 April is tracked in this series of Envisat images. On 17 and 19 April, the brown-coloured ash plume is visible travelling in a roughly southeasterly direction over the Atlantic Ocean by the prevailing western air current. By 20 April, much less ash is visible spewing from the volcano.
In the latest Envisat image acquired on 21 April at 13:36 CEST, even less ash is visible. Envisat has been monitoring the volcano since its recent eruptions began on 20 March. To see the latest Envisat satellite images over the area, simply visit our MIRAVI website. MIRAVI, which is free and requires no registration, generates images from the raw data collected by Envisat's Medium Resolution Imaging Spectrometer (MERIS) instrument and provides them online quickly after acquisition.
MERIS images provide visual clues of what is happening over the volcano and, furthermore, can provide information on the height of the ash plume in the atmosphere.
Scientists from the Free University of Berlin have developed an experimental algorithm for the retrieval of cloud-top height from measurements taken by MERIS between 17 – 19 April from 14:00 and 15:00 CEST.
The algorithm, which is operationally applied within the MERIS ground segment, is normally used to determine the height of clouds to support weather and precipitation forecasts. A similar algorithm, based on the exploitation of the height dependent oxygen absorption (~ 0.76 microns), is now being experimentally applied to determine the height of the ash cloud spewing from the volcanic eruption.
"We normally apply this method to clouds to determine their heights over ground. We have now applied the same technique to the ash plume from Iceland's volcano. The results show that the method works, and we can now provide the 'starting height' of the ash cloud and hope to be able to better predict the ash distribution in the future," said Prof. Juergen Fischer from the Free University of Berlin, who provided the height maps.
On 17 April, the ash plume reached a top height of more than 5 km close to its origin over the southern coast of Iceland with its top height dropping below 2 km as it travelled. On 19 April, the massive, wide-spread ash plume resided in the lower atmosphere close to the volcano with top heights below 2 km.
According to Prof. Fischer, these preliminary results agree with the volcanic plume heights established by research flights and forecasts by volcanic plume models. A more detailed algorithm dedicated to the height of volcanic ash clouds is currently under development.
Other satellite datasets as well as ground measurements are being used to measure the evolution of the ash cloud. To learn more about these, visit the links on the right.
Source: European Space Agency
Articles on the same topic
- Iceland volcano: Pitt researcher compiles first high-res images; plume receding but internal heat upFri, 23 Apr 2010, 17:39:40 UTC
- NASA's Terra satellite keeps eye on Eyjafjallajökull's ash plumeTue, 20 Apr 2010, 19:35:44 UTC
Other sources
- Iceland volcano: Pitt researcher compiles first high-res images; plume receding but internal heat upfrom Science BlogFri, 23 Apr 2010, 18:01:45 UTC
- Iceland volcano: Pitt researcher compiles first high-res images; plume receding but internal heat upfrom PhysorgFri, 23 Apr 2010, 18:01:42 UTC
- Iceland volcano tremors stay strong, ash plume lowfrom Reuters:ScienceThu, 22 Apr 2010, 12:11:25 UTC
- Cockpit audio: Listen as volcanic ash plume causes 1989 engine failure of KLM flight 867from PhysorgWed, 21 Apr 2010, 23:31:07 UTC
- Icelandic volcano no threat to climatefrom UPIWed, 21 Apr 2010, 23:00:42 UTC
- Envisat keeping an eye on the Eyjafjallajoekull volcanofrom PhysorgWed, 21 Apr 2010, 22:30:58 UTC
- Eyjafjallajokull Volcano's Ash Cloud Explainedfrom Live ScienceWed, 21 Apr 2010, 22:00:29 UTC
- Volcano Wreaking Havoc on Science Meetingsfrom Science NOWWed, 21 Apr 2010, 19:50:48 UTC
- Iceland’s Volcano Proving Tough to Predictfrom Science NOWWed, 21 Apr 2010, 19:50:46 UTC
- Iceland ash emissions at 'insignificant' level: expertfrom PhysorgWed, 21 Apr 2010, 18:01:30 UTC
- Envisat keeping an eye on the Eyjafjallajoekull volcanofrom European Space AgencyWed, 21 Apr 2010, 17:01:46 UTC
- Volcano Spews Less Ash as Lava Boils Upfrom CBSNews - ScienceWed, 21 Apr 2010, 16:21:31 UTC
- Iceland volcano spews less ash, eruption goes onfrom Reuters:ScienceWed, 21 Apr 2010, 15:00:16 UTC
- Terra Satellite Helps Measure Iceland Volcanic Plumefrom PhysorgWed, 21 Apr 2010, 12:30:52 UTC
- Threat of new, larger Icelandic eruption loomsfrom CBC: Technology & ScienceWed, 21 Apr 2010, 12:20:53 UTC
- NASA Satellite Helps Measure Iceland Volcanic Plumefrom NASA Jet Propulsion LaboratoryWed, 21 Apr 2010, 0:40:17 UTC
- Iceland volcano: news from the rimfrom The Guardian - ScienceWed, 21 Apr 2010, 0:30:32 UTC
- Image: NASA's Terra satellite keeps eye on Eyjafjallajokull's ash plumefrom PhysorgTue, 20 Apr 2010, 21:30:57 UTC
- NASA's Terra satellite keeps eye on Eyjafjallajökull's ash plumefrom Science BlogTue, 20 Apr 2010, 19:30:49 UTC